Endothecium, Tapetum, Epidermis ,Middle layers. These are the parts of anther wall .
(a ). Arrange them in an order according to occurrence in the anther wall .
(b) What is the function of tapetum ?

Explanation

(a)
(b) In embryo sac double fertilisation takes place .
The pollen tube releases the male gametes into the cytoplasm of the synergid .
The fusion of three haploid nuclei is termed fusion . Syngamy and triple fusion take place in embryo sac. This phenome non is termed double fertilization